Canning Spinach and Other Greens
Vegetables must be canned in a pressure canner for the correct time and pressure (PSI) to ensure their safety. If not canned correctly, these low acid foods may contain the deadly botulism toxin.
Vegetables may be canned without salt. Salt adds flavor but does not prevent spoilage. If you use a weighted-gauge canner and can at an altitude less than 1000 feet, you may use 10 PSI instead of 15 PSI for the canner pressure. This will improve nutrient and quality retention of the vegetables. Check with your local county extension office or Soil Conservation District for altitude information.
Quantity: An average of 28 pounds is needed per canner load of 7 quarts; an average of 18 pounds is needed per canner load of 9 pints. A bushel weighs 18 pounds and yields 3 to 9 quarts – an average of 4 pounds per quart.
Quality: Can only freshly harvested greens. Discard any wilted, discolored, diseased, or insect-damaged leaves. Leaves should be tender and attractive in color.
Procedure: Wash only small amounts of greens at one time. Drain water and continue rinsing until water is clear and free of grit. Cut out tough stems and midribs. Place 1 pound of greens at a time in a cheesecloth bag or blancher basket and steam 3 to 5 minutes or until well wilted. Add 1/4 teaspoon salt to pints; 1/2 teaspoon salt to quarts, if desired. Fill jars loosely with greens and add fresh boiling water, leaving 1 inch headspace. Adjust lids and process.
Dial-gauge Pressure Canner
Pints – 70 minutes 11 PSI
Quarts – 90 minutes 11 PSI
Weighted-gauge Pressure Canner
Pints – 70 minutes 15 PSI
Quarts – 90 minutes 15 PSI